[Osteosarcoma Secondary to Polyostotoic Fibrous Dysplasia of the Ribs].

Sarcomatous transformation of fibrous dysplasia is extremely rare. We present the case of a 54-yearold man with multiple rib masses, multiple enlarged lymph nodes throughout the body, and multiple osteolytic lesions on computed tomography( CT). A positron emission tomography( PET) scan showed abnormal enhancement in each. A needle biopsy of the right supraclavicular fossa lymph node revealed sarcoidosis. Considering the possibility of malignancy associated with sarcoidosis, a rib tumor resection and mediastinal lymph node biopsy were performed to confirm the diagnosis of the rib lesion. The pathology results showed that the rib mass was a low-grade central osteosarcoma and the mediastinal lymph node was sarcoidosis. The distribution of the lesions was consistent with osteosarcoma secondary to multiple fibrous bone dysplasia. As the osteosarcoma was low grade, the patient was followed up. Three years after surgery, there was no increase in residual disease.

Fibrocartilaginous Dysplasia of the Proximal Femur in Two Pediatric Patients, Including a Pathologic Fracture in a Patient With McCune-Albright Syndrome.

Fibrocartilaginous dysplasia (FCD) is a variant of fibrous dysplasia that often involves the proximal femur in young adults. It has a similar appearance on imaging as other entities but has stippled calcifications within the lesion. The differential diagnosis often includes benign and malignant tumors such as fibrous dysplasia, chondroblastoma, enchondroma, and chondrosarcoma. Histology is required for diagnosis and treatment is typically surgical due to the potential for pain, pathologic fracture, and deformity. We report the clinical presentation, imaging findings, and management of two pediatric patients with fibrocartilaginous dysplasia of the proximal femur to (1) highlight that recognition that fibrous dysplasia may contain cartilage upon frozen section will avoid overly aggressive therapy, and (2) FCD can occur in the McCune-Albright syndrome.

Clinical course of peripheral precocious puberty in girls due to autonomous ovarian cysts.

OBJECTIVE: Peripheral precocious puberty (PPP) is the precocious development of secondary sexual characteristics without pulsatile gonadotropin-releasing hormone (GnRH) secretion. In girls, PPP suggests a hyper-oestrogenic state, such as autonomous ovarian cysts and McCune-Albright syndrome (MAS). We aimed to investigate PPP in girls with ovarian cysts, with or without MAS. DESIGN: A retrospective study design was used. PATIENTS AND MEASUREMENTS: The study included 12 girls diagnosed with ovarian cysts with PPP between January 2003 and May 2022. Pelvic sonography was performed in cases of vaginal bleeding or areolar pigmentation in PPP. The clinical characteristics, clinical course and pelvic sonographic findings of girls with ovarian cysts were investigated. RESULTS: We found 18 episodes of ovarian cysts in the 12 girls. The median size of the ovarian cysts was 27.5 mm. Five of the girls were diagnosed with MAS. The median time to spontaneous regression was 6 months. Later, 4 out of 12 girls progressed to central precocious puberty (CPP), and three of them had a recurrence of ovarian cysts. Compared to the non-recurrent and recurrent groups, there was a difference in peak luteinizing hormone (LH) in the GnRH stimulation test and period to cyst regression. CONCLUSIONS: Most ovarian cysts in PPP spontaneously disappear. However, this could be one of the findings of MAS. Some girls progress from PPP to CPP. Therefore, follow-up is necessary for ovarian cysts in patients with PPP. The recurrence of ovarian cysts may occur when spontaneous regression is prolonged.

[The enigma of Henry IV's disease: Did he suffer from McCune-Albright syndrome/fibrous dysplasia?] / El enigma de la enfermedad de Enrique IV, rey de Castilla: ¿padeció síndrome de McCune-Albright/displasia fibrosa?

BACKGROUND: Henry IV King of Castile, last king of the Trastámara dynasty, was the brother of Isabella the Catholic. He is known as "the impotent". Based on previous descriptions by historians and biographers, Gregorio Marañón in 1922 described him as "eunuchoid dysplastic with acromegalic reaction and clear schizoid features". METHODS: In 1946, a post-mortem inspection was carried out on the mummified corpse found in the Monastery of Guadalupe. A written document and some photographs were recorded. We have collected the signs and symptoms described and applied the international classification of diseases recommended by the World Health Organisation, ICD11-2023. We have relied on the coins issued in the money of Henry IV, on which we have identified enlargement of the thyroid gland. RESULTS: With the data available at this time, we suggest that Henry IV most probably suffered from: facial and polyostotic bone dysplasia, kyphosis, limb limping, multiple endocrine disorders, acromegaly with macrognatia, nodular thyroid disease, malodorous diaphoresis, erectile dysfunction, hypospadias, abnormal sexual development, "feminoid pelvis", abdominal colic, oligodontia and dental displacement. It is possible that he also suffered from: precocious puberty, renal lithiasis with debilitating phosphaturia, carpal tunnel, thrombopenia and growth hormone-producing pituitary hyperplasia or adenoma. CONCLUSION: We suggest that Henry IV may have suffered from McCune-Albrigth syndrome associated with fibrous dysplasia, a rare disease due to gain-of-function mutations in the GNAS gene.

Efficacy of antiresorptive agents in fibrous dysplasia and McCune Albright syndrome, a systematic review and meta-analysis.

Fibrous dysplasia (FD) is a rare skeletal disorder in which normal bone is replaced by a fibro-osseous tissue, resulting in possible deformities and fractures. The aim of this systematic review and meta-analysis was to synthesize the available evidence on the use of antiresorptive drugs in FD in terms of changes in bone turnover markers (BTMs), bone mineral density (BMD), and reducing pain. Three databases were searched in October 2022, with an update in July 2023. Of the 1037 studies identified, 21 were retained after eligibility assessment. A random-effects model was used to calculate global effect size and the corresponding standard error. Pamidronate and Denosumab were the most reported drugs in a total of 374 patients assessed. The initiation of treatments was accompanied by an average reduction of 40.5% [CI95% -51.6, -29.3] in the bone resorption parameters, and 22.0% [CI95% -31.9, -12.1] in the parameters of bone formation after 6-12 months. BMD was increased in both FD lesions and in the unaffected skeleton. Pain was reduced by 32.7% [CI95% -52.7, -12.6] after 6-12 months of treatment, and by 44.5% [CI95% -65.3, -23.6] after a mean 41.2 months of follow-up. The variation in pain was highly correlated to variation in bone resorption (R2 = 0.08, p < 0.0001) and formation parameters (R2 = 0.17, p < 0.0001). This study supports the overall efficacy of antiresorptive therapies in terms of reducing bone remodeling, improving bone density, and pain in FD.

Case Report: Severe McCune-Albright syndrome presenting with neonatal Cushing syndrome: navigating through clinical obstacles.

Background: Café-au-lait skin macules, Cushing syndrome (CS), hyperthyroidism, and liver and cardiac dysfunction are presenting features of neonatal McCune-Albright syndrome (MAS), CS being the rarest endocrine feature. Although spontaneous resolution of hypercortisolism has been reported, outcome is usually unfavorable. While a unified approach to diagnosis, treatment, and follow-up is lacking, herein successful treatment and long-term follow-up of a rare case is presented. Clinical case: An 11-day-old girl born small for gestational age presented with deterioration of well-being and weight loss. Large hyperpigmented macules on the trunk, hypertension, hyponatremia, hyperglycemia, and elevated liver enzymes were noted. ACTH-independent CS due to MAS was diagnosed. Although metyrapone (300 mg/m2/day) was started on the 25th day, complete remission could not be achieved despite increasing the dose up to 1,850 mg/m2/day. At 9 months, right total and left three-quarters adrenalectomy was performed. Cortisol decreased substantially, ACTH remained suppressed, rapid tapering of hydrocortisone to physiological dose was not tolerated, and supraphysiological doses were required for 2 months. GNAS analysis from the adrenal tissue showed a pathogenic heterozygous mutation. During 34 months of follow-up, in addition to CS due to MAS, fibrous dysplasia, hypophosphatemic rickets, and peripheral precocious puberty were detected. She is still regularly screened for other endocrinopathies. Conclusion: Neonatal CS due to MAS is extremely rare. Although there is no specific guideline for diagnosis, treatment, or follow-up, addressing side effects and identifying treatment outcomes will improve quality of life and survival.

Lower-limb intramedullary nailing in patients with polyostotic fibrous dysplasia who had a previous unsuccessful treatment. A report of 48 cases.

BACKGROUND: Intramedullary nailing (IN) seems to be the best primary surgical treatment for patients with either polyostotic fibrous dysplasia or McCune-Albright syndrome (PFD/MAS) when the femur and tibia are totally affected by fibrous dysplasia (FD) and pain, fracture and deformity are likely to occur. However, other management protocols have been applied in these cases, often leading to disabling sequelae. This study sought to evaluate if IN could also have been effective as a salvage procedure to provide patients with satisfactory results, regardless of the poor results due to the improper treatment previously performed. MATERIALS AND METHODS: Twenty-four retrospectively registered PFD/MAS patients with 34 femurs and 14 tibias totally affected by fibrous dysplasia had received various treatments with unsatisfactory results in other institutions. Before the IN performed in our hospital, 3 patients were wheelchair bound; 4 were fractured; 17 limped; and many used an aid for walking. Salvage IN was performed in our hospital at a mean patient age of 23.66 ± 6.06 years (range, 15-37 years). The patients were evaluated before-except for the four fractured ones-and after IN using the validated Jung scoring system, and the data were statistically analyzed. RESULTS: The mean length of follow-up after IN was 9.12 ± 3.68 years (range, 4-17 years). The patients' mean Jung score significantly improved from 2.52 ± 1.74 points before IN to 6.78 ± 2.23 at follow-up (p < 0.05). Ambulation was improved in ambulatory patients and restored in wheelchair users. The complication rate was 21%. CONCLUSIONS: Regardless of the high rate of complications, IN may be considered a reliable surgical procedure to salvage a failed treatment in PFD/MAS, with long-lasting satisfactory results achieved in most patients. Trial registration statement: Not applicable. LEVEL OF EVIDENCE: IV.

Lesion Expansion in Gnathic Fibrous Dysplasia: Natural History, Indicators of Progression, and Response to Bisphosphonates.

Fibrous dysplasia (FD) is characterized by expansile fibro-osseous lesions that may occur in association with endocrinopathies as part of McCune-Albright syndrome (MAS). Craniofacial FD is a significant source of morbidity and most commonly involves the gnathic bones. There is a critical need to understand the natural history and risk factors for gnathic FD progression to develop preventative trials and identify candidates for intervention. The purpose of this study was to characterize gnathic FD lesion expansion and to identify risk factors associated with lesion growth. Patients with gnathic FD and serial CT imaging were evaluated. Volumetric analyses of CT scans were performed using MIM Encore software. Generalized mixed model analysis was used to account for intra-subject correlation, with FD lesion volume as the dependent variable. In addition to age, effects of MAS-associated endocrinopathies, sex, disease severity, and bisphosphonate treatment were evaluated. A total of 104 total lesions in 52 patients were characterized longitudinally. Median age at initial scan was 8.8 years (range 3.4-18.8), and median age at final scan was 16.8 years (range 6.9-33.4 years). The median number of scans per subject was 4 (range 2-14). FD lesion volume increased with age (2.50 cm3 /yr, 95% confidence interval [CI] 1.95-3.04, p < 0.001). However, lesion expansion rate decreased over time (-0.05 cm3 /yr, 95% CI -0.07 to 0.04, p < 0.001). Mandibular lesions tended to expand at a greater rate than maxillary lesions (p < 0.001). Growth hormone excess was associated with accelerated expansion rate (p = 0.002). Other MAS-associated endocrinopathies, pubertal status, sex, weight, lesion density, disease severity, and bisphosphonate treatment were not associated with lesion volume or expansion. Gnathic FD lesion expansion is most rapid in younger children and declines as patients approach adulthood. The availability of quantitative natural history data will guide clinicians in identifying patients who are candidates for medical and surgical interventions and clinical trials for preventative therapies. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.

Successful ART outcome in a woman with McCune-Albright syndrome: a case report and literature review.

McCune-Albright syndrome (MAS) is a rare genetic disease affecting multiple organs, including endocrine tissues. This endocrinopathy is sometimes responsible for infertility, as it may induce an independent functioning of the ovaries leading to anovulatory cycles. This case report describes the infertility journey of a 22-year-old female who had early puberty and irregular periods with high estrogen and progesterone levels, low FSH and LH (on day 3 of her menstrual cycle), and a multi-cystic right ovary. She received several infertility treatments: initially in vitro oocyte maturation (IVM) followed by cyst transvaginal ultrasound-guided aspiration, all unsuccessful. A right hemi-ovariectomy was performed that eventually restored regular cycles and made it possible to perform ovarian stimulation (OS) and in vitro fertilization (IVF). Live birth was obtained after the first embryo transfer.

Denosumab use in bone fibrous dysplasia refractory to bisphosphonate: A retrospective multicentric study.

INTRODUCTION: Increased RANKL expression is observed in the bone tissue of fibrous dysplasia of bone/McCune-Albright syndrome (FD/MAS). In one animal model of FD/MAS, the inhibition of RANKL reduced tumor volume. A beneficial effect of denosumab on pain in patients refractory to bisphosphonates has been reported, but without systematic quantification of pain improvement. This work describes the clinical experience of our group on the efficacy on pain of denosumab treatment, along with safety, in FD/MAS patients refractory to bisphosphonates. MATERIALS AND METHODS: We have conducted a retrospective multicenter study in 6 academic rheumatology centers in France. We have collected patients and FD/MAS characteristics, duration of prior exposure to bisphosphonates, denosumab treatment modalities (dosage - administration regimen - number of courses); evolution of pain evaluated by Visual Analogic Scale (VAS). RESULTS: 13 patients were included (10 women and 3 men) 45 years on average, 5 MAS, 4 monostotic and 4 polyostotic forms. The average duration post-diagnosis of FD/MAS was 25 years and the mean duration of prior exposure to bisphosphonates was 4.7 years. Pain could be analyzed in 7 patients, showing a significant improvement from a mean VAS of 7.8 to 2.9 (-4.9 points, p = 0.003). In one patient with fronto-orbital FD/MAS, a 30 % decrease in lesional volume, assessed by MRI, was observed within 6 months of treatment, that was sustained over the following 12 months. Treatment regimens were heterogeneous. No hypercalcemia was observed after treatment cessation and the clinical tolerance was good. DISCUSSION: This study suggests that denosumab reduces pain in patients with DF/MAS refractory to bisphosphonates, and quantifies this improvement for the first time in a multicenter study. In our cohort, no patients who discontinued denosumab developed hypercalcemia and clinical tolerance was overall good. This study also provides encouraging data regarding lesion volume control. Further controlled studies are required to determine the place and modalities of the denosumab treatment of FD/MAS. CONCLUSION: Denosumab significantly decreased pain in FD/MAS refractory to bisphosphonate. This study paves the way for a randomized clinical trial to validate and standardize the prescription of denosumab in FD/MAS.

[Further progress of the etiology,diagnosis and treatment of peripheral precocious puberty].

Peripheral precocious puberty(PPP),also known as puberty independent from hypothalamic-pituitary axis activation,is stimulated by hormones from other sources, with only partial sexual characteristics development but without mature sexual function. The secondary sexual characteristics development occurs before 7.5 years of age in girls and before 9 years of age in boys. Clinical manifestations are diverse, and PPP has varied etiology including congenital adrenal hyperplasia, McCune-Albright syndrome, ovarian cyst, adrenal tumor, ovarian tumor, testicular tumor, human chorionic gonadotropin producing tumor, familial male precocious puberty, aromatase excess syndrome, and environmental estrogen. Early identification of etiology, accurate differential diagnosis and prenatal gene screening play a significant role in the prevention, diagnosis and treatment of the disease.

Brain and eye involvement in McCune-Albright Syndrome: clinical and translational insights.

McCune-Albright Syndrome (MAS) is a rare mosaic (post-zygotic) genetic disorder presenting with a broad continuum clinical spectrum. MAS arises from somatic, activating mutations in the GNAS gene, which induces a dysregulated Gsα-protein signaling in several tissues and an increased production of intracellular cyclic adenosine monophosphate (cAMP). Overall, MAS is a rare disorder affecting less than 1/100,000 children and, for this reason, data establishing genotype-phenotype correlations remain limited. Affected individuals clinically present with a variable combination of fibrous dysplasia of bone (FD), extra-skeletal manifestations (including cafeí-au-lait spots) and precocious puberty which might also be associated to broad hyperfunctioning endocrinopathies, and also gastrointestinal and cardiological involvement. Central nervous system (CNS) and eye involvement in MAS are among the less frequently described complications and remain largely uncharacterized. These rare complications mainly include neurodevelopmental abnormalities (e.g., delayed motor development, cognitive and language impairment), CNS anomalies (e.g., Chiari malformation type I) and a wide array of ophthalmological abnormalities often associated with vision loss. The pathophysiological mechanisms underlying abnormal neurological development have not been yet fully elucidated. The proposed mechanisms include a deleterious impact of chronically dysregulated Gsα-protein signaling on neurological function, or a secondary (damaging) effect of (antenatal and/or early postnatal) hypercortisolism on early pre- and post-natal CNS development. In this Review, we summarize the main neurological and ophthalmological features eventually associated with the MAS spectrum, also providing a detailed overview of the potential pathophysiological mechanisms underlying these clinical complications.

McCune-Albright Syndrome: A Case Report and Review of Literature.

McCune-Albright syndrome (MAS) is a rare sporadic condition defined by the classic triad of fibrous dysplasia of bone, café au lait skin macules, and hyperfunctioning endocrinopathies. The molecular basis of MAS has been ascribed to the post-zygotic somatic gain-of-function mutations in the GNAS gene, which encodes the alpha subunit of G proteins, leading to constitutive activation of several G Protein-Coupled Receptors (GPCRs). The co-occurrence of two of the above-mentioned cardinal clinical manifestations sets the diagnosis at the clinical level. In this case report, we describe a 27-month-old girl who presented with gonadotropin-independent precocious puberty secondary to an estrogen-secreting ovarian cyst, a café au lait skin macule and growth hormone, and prolactin excess, and we provide an updated review of the scientific literature on the clinical features, diagnostic work-up, and therapeutic management of MAS.

Coxa Vara Deformity in Fibrous Dysplasia/McCune-Albright Syndrome: Prevalence, Natural History and Risk Factors: A Two-Center Study.

This study aimed to evaluate the prevalence of and risk factors for coxa vara deformity in patients with fibrous dysplasia/McCune-Albright syndrome (FD/MAS). This study was conducted at the National Institutes of Health and Leiden University Medical Center. All patients with any subtype of FD/MAS, FD involving the proximal femur, one or more X-rays available and age <30 years were included. X-rays were scored for the neck-shaft angle (NSA). Varus deformity was defined as NSA <110 degrees or >10 degrees below age-specific values. Risk factors for deformity were assessed by nested case-control analysis, comparing patients and femurs with and without deformity, and by linear mixed effects model, modeling temporal NSA decrease (the natural course of the NSA) in non-operated femurs with two or more X-rays. Assessed variables included growth hormone excess, hyperthyroidism, hypophosphatemia, >25% of the femur affected, calcar destruction, radiolucency, and bilateral involvement. In total 180 patients were studied, 57% female. Mean ± SD baseline age was 13.6 ± 7.5 years; median follow-up 5.4 (interquartile range [IQR], 11.1) years. Sixty-three percent (63%) were diagnosed with MAS. A total of 94 patients were affected bilaterally; 274 FD femurs were analyzed; 99 femurs had a varus deformity (36%). In the nested case-control analysis, risk factors were as follows: presence of MAS (p < 0.001), hyperthyroidism (p < 0.001), hypophosphatemia (p < 0.001), high percentage of femur affected (p < 0.001), and calcar destruction (p < 0.001). The linear mixed effects model included 114 femurs, identified risk factors were: growth hormone excess (ß = 7.2, p = 0.013), hyperthyroidism (ß = 11.3, p < 0.001), >25% of the femur affected (ß = 13.2, p = 0.046), calcar destruction (ß = 8.3, p = 0.004), radiolucency (ß = 3.9, p = 0.009), and bilateral involvement (ß = 9.8, p = 0.010). Visual inspection of the graph of the model demonstrated most progression of deformity if NSA <120 degrees with age < 15 years. In conclusion, in tertiary care centers, the prevalence of FD/MAS coxa vara deformity was 36%. Risk factors included presence of MAS, high percentage of femur affected, calcar destruction, radiolucency, NSA <120 degrees and age < 15 years. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Autonomous growth hormone secretion due to McCune Albright syndrome in paediatric age group: an ominous triad.

PURPOSE: The current study aimed to report cases of McCune Albright syndrome (MAS) with growth hormone (GH) hyper secretion along with a systematic review of literature to elucidate challenges and intricacies in its diagnosis and management. METHODS: It was a single centre study carried out in individuals with MAS and autonomous GH secretion (AGHS). In addition, a systematic search of literature across three databases (PubMed, Scopus and EMBASE) was performed from inception until May 31, 2021 to identify cases of MAS with AGHS in the pediatric age group (<18 years). RESULTS: Three cases from authors centre and 42 cases identified from systematic literature review were analysed. Precocious puberty was the most common presenting endocrinopathy seen in 56.8% (25/44) cases, followed by hyperthyroidism (10/45), hypophosphatemia (4/45), and hypercortisolism (2/45). Cranio-facial fibrous dysplasia (CFFD) was seen in all while polyostotic fibrous dysplasia and Café au lait macule was seen in 40/45 (88.9%) and 35/45 (77.8%), respectively. Pituitary adenoma (58.3% microadenoma) was localized in 53.3% (24/45) cases on pituitary imaging. Biochemical and clinical remission of AGHS was achieved in 61.5% (24/45) cases with medical therapy. CONCLUSION: Diagnosing AGHS in MAS is challenging because of concomitant presence of CFFD, non-GH endocrinopathies associated height spurt and elevated serum IGF-1. GH-GTT should be performed in presence of elevated growth velocity and serum IGF-1 (>1 X ULN) despite adequate control of non-GH endocrinopathies. Medical management can lead to disease control in substantial number of cases and often entails use of multiple agents.

Craniofacial Fibrous Dysplasia: Clinical and Therapeutic Implications.

PURPOSE OF REVIEW: This study aims to review diagnosis, potential complications, and clinical management in craniofacial fibrous dysplasia. RECENT FINDINGS: Fibrous dysplasia (FD) is a rare mosaic disorder in which normal bone and marrow are replaced with expansile fibro-osseous lesions. Disease presents along a broad spectrum and may be associated with extraskeletal features as part of McCune-Albright syndrome (MAS). The craniofacial skeleton is one of the most commonly impacted areas in FD, and its functional and anatomical complexities create unique challenges for diagnosis and management. This review summarizes current approaches to diagnosis and management in FD/MAS, with emphasis on the clinical and therapeutic implications for the craniofacial skeleton.

Pharmacological Interventions Targeting Pain in Fibrous Dysplasia/McCune-Albright Syndrome.

Fibrous dysplasia (FD) is a rare, non-inherited bone disease occurring following a somatic gain-of-function R201 missense mutation of the guanine-nucleotide binding protein alpha subunit stimulating activity polypeptide 1 (GNAS) gene. The spectrum of the disease ranges from a single FD lesion to a combination with extraskeletal features; an amalgamation with café-au-lait skin hyperpigmentation, precocious puberty, and other endocrinopathies defines McCune-Albright Syndrome (MAS). Pain in FD/MAS represents one of the most prominent aspects of the disease and one of the most challenging to treat-an outcome driven by (i) the heterogeneous nature of FD/MAS, (ii) the variable presentation of pain phenotypes (i.e., craniofacial vs. musculoskeletal pain), (iii) a lack of studies probing pain mechanisms, and (iv) a lack of rigorously validated analgesic strategies in FD/MAS. At present, a range of pharmacotherapies are prescribed to patients with FD/MAS to mitigate skeletal disease activity, as well as pain. We analyze evidence guiding the current use of bisphosphonates, denosumab, and other therapies in FD/MAS, and also discuss the potential underlying pharmacological mechanisms by which pain relief may be achieved. Furthermore, we highlight the range of presentation of pain in individual cases of FD/MAS to further describe the difficulties associated with employing effective pain treatment in FD/MAS. Potential next steps toward identifying and validating effective pain treatments in FD/MAS are discussed, such as employing randomized control trials and probing new pain pathways in this rare bone disease.

Burosumab Therapy in a Paediatric Patient with McCune-Albright Syndrome: A Case Report.

INTRODUCTION: McCune-Albright syndrome is characterized by the triad of fibrous dysplasia, café au lait skin pigmentation, and hyperfunctioning endocrinopathies. It is a sporadic condition caused by a missense mutation in the GNAS locus, located on chromosome 20q13.3, resulting in mosaic activation of the G protein alpha subunit. CASE PRESENTATION: We pre­sent a paediatric patient diagnosed with McCune-Albright syndrome at the age of 5 years. During the course of his condition, he was medically managed for a number of complications, such as peripheral precocious puberty and growth hormone excess, and monitored for hyperprolactinaemia. Due to fibroblast growth factor 23-mediated phosphate wasting, the patient was commenced on oral phosphate supplements and alfacalcidol. After 2 years of treatment, this therapy did not optimize his bone biochemistry (phosphate 0.96 mmol/L, alkaline phosphatase 1,172 IU/L, and parathyroid hormone 9.1 pmol/L), and the patient was started on two-weekly burosumab therapy via subcutaneous injection. His bone biochemistry soon normalized (phosphate 1.52 mmol/L, alkaline phosphatase 358 IU/L, and parathyroid hormone 6.9 pmol/L) following this, and he remains on burosumab without any adverse effects. DISCUSSION: This case shows the positive effect that a short-term course of burosumab has on bone health in a paediatric patient with McCune-Albright syndrome. Further research is required to assess long-term effects. Our patient also presented with precocious puberty and growth hormone excess, a coexistence that can be challenging to diagnose and is less common in males. He received medical management for both conditions, but due to the similar presentations, this case highlights the importance to investigate and diagnose associated complications as early as possible, so they can be managed in a timely manner.

Hyperthyroidism in McCune-Albright Syndrome - a case report.

OBJECTIVES: We intend to describe a case of McCune-Albright Syndrome (MAS), a rare disease characterized by fibrous dysplasia (FD), cutaneous hyperpigmentation and hyperfunctioning endocrinopathies (HFE). CASE PRESENTATION: We report the case of a 13-year-old male child who presented with a café-au-lait macule in the lumbosacral region and disabling polyostotic FD, requiring several surgical interventions and bisphosphonates from the age of 3 years (Y) + 9 months (M) due to persistent and severe pain. Hyperthyroidism (HT) became apparent at 5 Y + 1 M with a T3/T4 ratio greater than 20. Treatment with anti-thyroid drugs (ATD) was carried out for 7 Y and there was a progressive improvement in pain complaints 8 M after starting ATD, allowing treatment with pamidronate to be discontinued. Total thyroidectomy was performed at 12 Y + 5 M. CONCLUSIONS: This is a case of MAS-associated HT that reflects the deleterious effect of thyroid hormone excess on FD, reinforcing the need of having a low threshold for suspicion of HFE that may arise.